A gas turbine is a heat engine that drives a turbine by using a combustion gas of high temperature and high pressure, and generally includes a compressor, a combustor, and a turbine. The compressor compresses air, the combustor burns the air by injecting fuel, and then, the air of high temperature and high pressure expands in the turbine to generate a driving power.
A region, where flames are not swept but fixed at an appropriate position, in the combustor is referred to as a central recirculation zone (CRZ). In order to maintain the combustion continuously and to prompt mixture of the fuel and an oxidizing agent in the combustor, it is important to maintain an appropriate CRZ according to flow. That is, in order to maintain the CRZ, a swirl component has to be applied to the flow.